The goal of these lectures will be to explain the progress made in studying BHs in the context of string theory with a particular focus on addressing issues such as information loss and BH entropy. The general outline of the lectures will be as follows: \ 1. Black holes from D-branes in string theory & supergravity. \ 2. BH entropy via D-branes: Strominger-Vafa, Maldacena-Strominger-Witten. \ 3. AdS-CFT description of black holes. \ 4. Information paradox within string theory & AdS-CFT. \ 5. Fuzzballs and BH Hair: multicenter solutions. \ 6. BPS/non-BPS fuzzballs. \ 7. Macroscopic quantum effects and horizon-scale non-locality. \ \ \ (Cours organisés en collaboration avec l'Ecole Doctorale de Physique de la Région Parisienne - ED 107)